Gov. Andrew M. Cuomo's NY Sun initiative is raising the interest rates on a popular state-subsidized loan program that helps defray the cost of home solar installations and energy-efficiency work.

In an alert to solar installers last week, the New York State Energy Research & Development Authority said it's raising the rates by as much as 6 percentage points as a way to continue the loan program in a "sustainable manner."

The program, administered through Cuomo's Green Jobs-Green New York initiative, provides loans of up to $25,000 at annual interest rates as low as 3.49 percent to pay the cost of solar installations, as well as for other energy-efficiency improvements and related work. Customers repay the loans on their monthly energy bills, which cannot increase more than they had been before the installation.

Solar panels can reduce an energy bill to near zero, so most of the monthly payment pays off the long-term loan. The NYSERDA loans are paid back over five, 10 or 15 years.

In February, rates for those who are not considered low- to moderate-income earners will jump to 4.99 percent for those earning more than 80 percent of the median income for their area and 5.99 percent for those earning more than 120 percent of that level. NYSERDA defines low-to-moderate income as those earning 80 percent or less of the area's median household income, or $84,133 for a family of four on Long Island.

In April, the rates will jump again for those earning more than 120 percent of the median income, to 7.99 percent for efficiency work and 9.99 percent for solar installations.

Kevin MacLeod, a member of the Long Island Solar Energy Industries Association and a solar installer at KPS Solar in Bay Shore, predicted the cuts will have the biggest impact on companies that sell solar systems to residents rather than lease them.

"It is obvious that the state wants completely out of the solar program," he said. "No rebates and no loans."

MacLeod said the effect of the changes is that biggest users of the program in mid- to higher-income brackets will be "forced to use the higher interest rates" or, more likely, not use it at all. Since those rates are "not as competitive, not many will go for it, especially if NYSERDA makes the credit criteria tougher," he said.

Despite reports to the contrary, the loan program on Long Island isn't going to end on March 31, a NYSERDA source said.

The agency had been examining ways to continue it in the face of state-subsidized loans at the 3.49 percent-to-3.99 percent level that amounted to a loss with each transaction. Increasing the rates for higher-income earners, the source said, will help address that issue.The expiration comes as a separate state-subsidized rebate program is also close to running out of money for Long Island. Only around $1.6 million remains in that fund, according to the state's website.

Even with the state's solar-loan program about to end for most Long Islanders, the loans for efficiency work -- replacing doors and windows and modernizing lighting systems -- will continue. But the loans by April will be roughly competitive with local bank loans -- 7.99 percent for those earning 120 percent of the area median income. In the rest of the state, the rate for solar loans jumps to 9.99 percent for those in that earning category.